A Liquid Crystal Display (LCD) has many advantages of thin body, low power consumption, no radiation and son on such that the LCD is widely applied in a mobile telephone, a personal digital assistant (PDA), a digital camera, a laptop computer screen. The LCD in the current market is mainly a backlight type LCD, which includes a frame, a liquid crystal display panel disposed inside the frame and a backlight module inside the frame.
A hot technology in the current market is using a quantum dot to improve the gamut of the backlight. The quantum dot is a nanomaterial with quasi zero dimension, and is formed by a small number of atoms; the particle size is generally ranged from 1 nm to 10 nm. Because electrons and holes are limited by quantum, the continuous band structure becomes discrete band structure. After excited, a florescent light is emitted in order to change the gamut of an incident light. The quantum dot backlight technology can increase the gamut of a display device up to 100%. The conventional quantum dot backlight technology mainly has two types. One is to discretely coat the quantum dots on a polyester film in order to replace a diffusion film. The other is packaging the quantum dot into a glass tube, and placing the glass tube between a blue LED and a light guide plate. However, the quantum dot thin film is easily to be affected by the external condition as water and oxygen, and when cutting the edge of the thin film, some water and oxygen will penetrate so that an edge failure problem is generated. The main reason is that the particle size of a green quantum dot is smaller than the particle size of a red quantum dot, and a surface energy is high so that the green quantum dot is easily to react with water and oxygen so as to be fail. Therefore, the failure region presents a fuchsia color.